The effects of mechanical forces on bones and joints. Experimental study on the rat tail.

We have used an experimental model employing the bent tail of rats to investigate the effects of mechanical forces on bones and joints. Mechanical strain could be applied to the bones and joints of the tail without direct surgical exposure or the application of pins and wires. The intervertebral disc showed stretched annular lamellae on the convex side, while the annulus fibrosus on the concave side was pinched between the inner corners of the vertebral epiphysis. In young rats with an active growth plate, a transverse fissure appeared at the level of the hypertrophic cell layer or the primary metaphyseal trabecular zone. Metaphyseal and epiphyseal trabeculae on the compressed side were thicker and more dense than those of the distracted part of the vertebra. In growing animals, morphometric analysis of hemiepiphyseal and hemimetaphyseal areas, and the corresponding trabecular bone density, showed significant differences between the compressed and distracted sides. No differences were observed in adult rats. We found no significant differences in osteoclast number between compressed and distracted sides in either age group. Our results provide quantitative evidence of the working of 'Wolff's law'. The differences in trabecular density are examples of remodelling by osteoclasts and osteoblasts; our finding of no significant difference in osteoclast numbers between the hemiepiphyses in the experimental and control groups suggests that the response of living bone to altered strain is mediated by osteoblasts

The reaction to nailing or cementing of the femur in rats. A microangiographic and fluorescence study.

Bone reaction to cement and to a cementless stem was studied in the rat femur with histological fluorescence and microangiographic techniques. Periosteal and endosteal apposition, and consequent remodelling, appeared as a reaction to reaming rather than caused by cement or a cementless stem. Every change in bone began with proliferation, progression and orientation of the vessels. Endosteal apposition was absent in cemented femurs because the entire medulla was occupied by the acrylic cement, but remodelling of the subendosteal cortex followed medullary revascularisation which was far advanced after 90 days. In cementless stems, endosteal apposition of primary woven bone and remodelling was the basis for bony ingrowth and anchorage through bony bridges. Our results suggest that the pattern of blood supply is relevant to the structural organisation of mature lamellar bone around the implant. Cemented stems have maximum anchorage and stability as soon as they are inserted, but this decreases with time as revascularisation occurs. Cementless stems can reach maximum integration later after insertion, and revascularisation is less critical because they usually do not fill the canal completely

Pathology of disappearing bone disease: a case report with immunohistochemical study.

A case of disappearing bone disease of the proximal femur is reported with histopathological and immunohistochemical studies. There was a densely packed cellular tissue, positive to endothelial antibodies, in areas of massive bone destruction. A more differentiated vascular tissue was present where trabecular cancellous or cortical bone was preserved with only focal zones of accelerated bone remodelling. The self-limited course correlates well with two phases of evolution of the histopathological lesions with neoplastic-like proliferation of endothelial cells corresponding to the rapid and massive bone destruction, and a later differentiation of the cells in mature vascular structures, but still with accelerated bone resorption which is partly compensated by appositional activity

The relevance of hydroxyapatite and spongious titanium coatings in fixation of cementless stems. An experimental comparative study in rat femur employing histological and microangiographic techniques.

Pure titanium rods plasma-spray coated with hydroxyapatite (HA) or porous titanium (Ti) of controlled roughness were implanted bilaterally in the distal femur of Sprague-Dawley rats to compare the extent of bone growth on the two types of coating. The relevance of other factors, like mechanical stability and biological adaptation of the bone to the insertion of a foreign body implant, were investigated in femora which were over-reamed (absence of primary fit) or reamed without insertion of the rod. Continuous tetracycline labeling for the first 30 days and for the last 2 weeks in the 90-day group was performed; histological/histometric, fluorescence and microangiographic studies were carried out on serial sections of the implanted and control femora. In the group of stable implants, HA-coated rods showed 90% integration versus 53% with Ti-coated implants (P < 0.001); in over-reamed implants neither surface bone growth nor endosteal fixation occurred, and both types of rods were surrounded by a thick layer of connective tissue. The study documented early adhesion of osteoblasts and direct deposition of bone matrix on the substrate, while on spongious titanium osteogenesis was observed only in proximity to the surface. Remodeling of the reactive, primary bone to mature, lamellar bone took the form of a capsule surrounding the implants and radial bridges connecting the latter to the endosteal surface. The number, height and thickness of these bridges appeared to be the factors determining implant stability, rather than the extent of the bony capsule on the perimeter of the implant. Integration was a function not only of mechanical conditions and surface geometry, but also of the biological response of the whole bone to changes in the vascularization pattern. The reported phenomena can be seen more easily in experimental models involving small rodents because of their fast bone turnover and revascularization, but it is expected that they take place, even at a lower speed, in clinical situations like cementless stems of total hip replacement

An Update on Appendiceal Neuroendocrine Tumors

The mainstay of appendiceal neuroendocrine neoplasm (aNEN) treatment is surgery, based on simple appendectomy or right-sided hemicolectomy with lymphadenectomy (RHC). The majority of aNENs are adequately treated with appendectomy, but current guidelines have poor accuracy in terms of selecting patients requiring RHC, especially in aNENs 1–2&nbsp;cm in size. Simple appendectomy is curative for appendiceal NETs (G1–G2) &lt; 1&nbsp;cm (if the resection status is R0), whereas RHC with lymph node dissection is recommended in tumors ≥ 2&nbsp;cm in diameter, based on the high risk of nodal metastases in these cases. The clinical management of aNENs 1–2&nbsp;cm in size is more controversial because lymph node or distant metastases are uncommon but possible. In our opinion, patients with tumor size &gt; 15&nbsp;mm or with grading G2 (according to WHO 2010) and/or lympho-vascular invasion should be referred for radicalization with RHC. However, decision-making in these cases should include discussion within a multidisciplinary tumor board at referral centers with the aim of offering each patient a tailored treatment, also considering that relatively young patients with long-life expectancy represent the majority of cases

Functional Seizures: The Patient’s Perspective of a Diagnostic and Treatment Odyssey

Functional seizures can be challenging to properly diagnose, often leading to delays in treatment. The etiology of functional seizures is multifactorial, with psychological factors identified in many, but not all cases. Misdiagnosis may occur due to clinical features mimicking other medical conditions. Once a correct diagnosis is reached, delivery of definitive, evidence-based treatment may be challenging due to limited availability of specialized resources. Research shows psychological education and cognitive behavioral therapy (CBT) have the greatest efficacy. However, individual differences, including acceptance of the diagnosis, therapeutic alliance, duration of symptoms, comorbidities, and access to care may influence outcomes. There is a critical need for reports that can help identify barriers to effective diagnosis and treatment. We present the diagnosis and treatment of a woman who visited the emergency room after an attack of predominant left-sided paralysis, speech dysfunction and altered awareness. Following multiple daily episodes and visits to multiple medical practitioners, testing led to a diagnosis of functional seizures. While the patient was recommended to undergo a variety of therapeutic interventions, including CBT, she ultimately terminated treatment. In a subsequent interview, the patient revealed her personal experience with perceived limitations of acute management strategies. We explore the complexities of diagnosing and treating individuals with functional seizures

Expression of vascular endothelial growth factor in normal and tumoral liver mouse cells

In previous studies have been reported a controversy between the reactivity of mono and polyclonal antibodies in different cells populations of the mouse. In this study we focus on the immunoreactivity of the monoclonal antibody VEGF (C- 1) in order to analyze its expression in two cell populations of regenerating mouse liver (hepatocytes and endothelial cells) after partial hepatectomy, and two transplanted hepatocarcinomas (ES2 and SS1K). C3H/S male mice were divided into two groups and kept under standard conditions for circadian periodicity analysis, one group were transplanted with the tumors into the subcutaneous tissue of the animal flank and the other group were subjected to a partial hepatectomy (70 %). The animals were killed by decapitation and exsanguination. Samples of regeneration liver, ES2 and SS1K tumors were processed for histology and immunostained with VEGF (C-1) mouse monoclonal IgG2a antibody. The results showed strongly immunopositivity reaction for VEGF either in hepatocytes or endothelial cells of mouse regenerating liver. We also demonstrated positive immunoreaction in both malignant tumors ES2 and SS1K endothelial and parenchymal cells. We conclude that the use of VEGF (C-1) mouse monoclonal IgG2a antibody can be applied successfully in experimental design leading to study processes involved in mice’s angiogenesi

Estudio comparativo de la síntesis de ADN en hígado y riñón de ratones lactantes y adultos

In previous papers we have observed that the proliferative activity of numerous cell populations of suckling and young mice was different than the observed in adults. In the present work we analized the DNA synthesis of suckling and adult mice, by immunohistochemistry (Bromodioxiuridine) in both hepatocytes and renocytes, at two different time points. The object of the present experiment was to establish the correlation in cellular proliferation between both groups. We used C3HS suckling male mice of 21 days old and adult mice of 90 days old. The results showed that DNA synthesis of renocytes and hepatocytes in suckling mice were significantly higher than the adults, and we didn't find statistically differences between the values of both analysed time points. We can conclude that in suckling mice we could observe maximum and minimum values but we coudn't find a circadian rhythm like those established in adults.En trabajos previos hemos observado que la actividad proliferativa de numerosas poblaciones celulares del ratón lactante y joven difiere de la encontrada en el adulto. En el presente trabajo experimental, se estudia la síntesis de ADN del ratón lactante y adulto, mediante el método inmunohistoquímico de la Brdu (Bromodeoxiuridina), en las poblaciones celulares de hepatocitos y renocitos, a las OO:O0 h y 16:00 h, con el objeto de establecer la correspondencia en la proliferación celular entre ambos grupos etarios. Para ello se utilizaron machos lactantes de 21 días de edad y adultos de 90 días, de la cepa C3H/S. Los resultados muestran que los valores de síntesisde ADN de los renocitos y hepatodtos en los ratones lactantes son significativamente mayores (p<O.001) a los observados en los adultos, no encontrándose diferencias estadísticamente significativas entre los valores de ambos puntos horarios en los órganos estudiados. Podemos concluir que estos hallazgos demuestran que, si bien en los ratones lactantes aparecen valores máximos y mínimos en la actividad proliferativa de distintas poblaciones celulares, estas aún no presentan la ritmicidad establecida para los adultos

Expression of vascular endothelial growth factor in normal and tumoral liver mouse cells

In previous studies have been reported a controversy between the reactivity of mono and polyclonal antibodies in different cells populations of the mouse. In this study we focus on the immunoreactivity of the monoclonal antibody VEGF (C-1) in order to analyze its expression in two cell populations of regenerating mouse liver (hepatocytes and endothelial cells) after partial hepatectomy, and two transplanted hepatocarcinomas (ES2 and SS1K). C3H/S male mice were divided into two groups and kept under standard conditions for circadian periodicity analysis, one group were transplanted with the tumors into the subcutaneous tissue of the animal flank and the other group were subjected to a partial hepatectomy (70 %). The animals were killed by decapitation and exsanguination. Samples of regeneration liver, ES2 and SS1K tumors were processed for histology and immunostained with VEGF (C-1) mouse monoclonal IgG2a antibody. The results showed strongly immunopositivity reaction for VEGF either in hepatocytes or endothelial cells of mouse regenerating liver. We also demonstrated positive immunoreaction in both malignant tumors ES2 and SS1K endothelial and parenchymal cells. We conclude that the use of VEGF (C-1) mouse monoclonal IgG2a antibody can be applied successfully in experimental design leading to study processes involved in mice’s angiogenesisFacultad de Ciencias Médica